Bone formation is tightly regulated by osteoblasts, which secrete extracellular matrix (ECM) components and heterogeneous populations of extracellular vesicles (EVs). Among EVs, matrix vesicles (MVs) are uniquely associated with mineralization and act as bioactive extracellular nanostructures that initiate and spatially direct mineral growth within the ECM. However, how MVs interact with the ECM and how their functions differ from the functions of medium-derived EVs (mEVs) remain unclear. To address this question, we developed a bioinspired collagen-based scaffold designed to mimic the bone ECM organic phase and to recreate MV-mediated mineralization in vitro. Type I collagen scaffolds were slowly concentrated and exposed to NH3(g) to induce fibrillogenesis and stabilize supramolecular organization, while 5 wt % κ-carrageenan, a sulfated polysaccharide that functionally emulates glycosaminoglycans, was incorporated to support mineral nucleation. MC3T3-E1 pre-osteoblasts were cultured under osteogenic conditions to induce differentiation and vesicle secretion. Biochemical, microscopic, and spectroscopic analyses revealed that MVs and mEVs exhibit distinct nano-biointerface behaviors, particularly regarding ECM anchoring and the ability to initiate mineral deposition. Furthermore, Raman chemical imaging and X-ray nanotomography demonstrated that MVs not only trigger mineral formation but also direct the spatial organization of phosphate deposition within the ECM at the micro/nanoscale. By distinguishing MV- from mEV-mediated mineralization in a biomimetic ECM system, this study provides new insights into vesicle-guided biomineralization and spatial matrix organization, with implications for skeletal development, pathological calcification, and vesicle-based regenerative strategies.
Bioinspired and biomimetic membranes represent a rapidly advancing class of materials for biomedical and life-science applications by emulating the structure and function of natural biological systems. This review represents the current progress in these technologies, including membrane-coated nanoparticles, tissue-engineering scaffolds, and related constructs, and classifies them into four complementary functional categories. It further elaborates on material selection, fabrication methods, biomedical uses, translational barriers, and future directions. Natural biodegradable polymers contribute to biocompatibility and intrinsic bioactivity, whereas synthetic polymers afford adjustable mechanical properties and controlled degradation. Lipid-based formulations and cell membrane-mimetic nanostructures enhance functionality through improved targeting, immune evasion, and regulated drug release. Precise architectural control is achieved using advanced fabrication approaches such as electrospinning, layer-by-layer assembly, self-assembly, biomineralization, and 3D bioprinting. These membranes have shown in vitro experiments and preclinical animal studies, and for certain selected systems, such as dialysis membranes and liposomal systems, they have already reached clinical use for drug delivery, tissue regeneration, biosensing, and antimicrobial applications. Despite advances in recapitulating biological form and function, important obstacles remain, notably scalable manufacturing, long-term stability under physiological conditions, and cost-effectiveness. Nevertheless, owing to their selective molecular transport, adaptive behavior, and enhanced biointerface compatibility, bioinspired and biomimetic membranes are suitable materials for next-generation biomedical technologies.
Oral drug delivery is the most patient-friendly and safest approach for disease treatment; however, the bioavailability of macromolecular drugs and poorly soluble small molecules is severely limited by gastrointestinal degradation and the blood-brain barrier (BBB). Here, we developed a cost-effective, chitosan-based isolation method to efficiently isolate milk-derived extracellular vesicles (mEVs), which exhibit good stability in the gastrointestinal tract and intrinsic BBB-penetrating capability. Biodistribution studies showed that mEVs were absorbed in both healthy and experimental autoimmune encephalomyelitis (EAE) mice, with increased CNS accumulation under neuroinflammation, especially in oligodendrocytes and neurons. To address the poor stability and bioavailability of ellagic acid (EA) and to explore the therapeutic potential of mEVs in neuroinflammation treatment, we encapsulated EA and interferon-β (IFN-β) into mEVs and evaluated their therapeutic effects in experimental autoimmune encephalomyelitis (EAE) and lipopolysaccharide-induced neuroinflammation models. The results showed that mEV@IFN-β and mEV@EA significantly relieved disease progression and improved neuroinflammation compared to free drugs, with enhanced stability and bioavailability. Overall, our study findings establish mEVs as an efficient oral delivery platform capable of overcoming biological barriers for treating neuroinflammatory diseases, with the chitosan-based isolation method offering a scalable production approach.
Existing in vivo models for retinal pathologies are costly, time-consuming, and subject to regulatory challenges, promoting interest in advanced in vitro models that replicate the blood-retinal barrier. Challenges related to vascularization and structural multiscale interactions hinder the development of in vitro models, which are useful to study nutrient and drug exchange between the retina and systemic circulation. To address these issues, we developed a blood-retinal barrier in vitro model for studying retinal pathophysiology. It features an electrospun scaffold (Bruch's membrane) placed between a culture chamber (vitreous humor) and a bioinspired microfluidic network (choroidal vasculature). The network, modelled from indocyanine green angiography of the human retina, is laser-engraved into a 15 mm PDMS disc with channels 70-800 μm wide. PLGA and gelatin electrospun scaffold were investigated to mimic Bruch's membrane. The scaffold is fixed to the microfluidic network, assembled into a culture chamber, and integrated within a bioreactor. A peristaltic pump ensures a consistent flow in the channels. Biological validation included ARPE-19 cells cultured on Transwell, PLGA, or gelatin membranes, HUVECs within membrane-coupled microchannels, and dual-layer constructs. Cells were examined separately and together, allowing evaluation of epithelial, endothelial, and construct responses. All configurations showed progressive increases in metabolic activity and limited LDH release over 28 days. Cell-seeded constructs reduced FITC-dextran transport relative to acellular controls, with stable values between days 21 and 28. Blank-corrected TEER likewise increased during ARPE-19 culture and plateaued by day 21. PLGA constructs showed the greatest electrical and solute-transport resistance, although acellular controls confirmed a substantial material contribution. Confocal microscopy demonstrated HUVEC attachment and F-actin organization along the microchannels, while ARPE-19 monolayers exhibited continuous junction-associated ZO-1 staining that remained stable between days 21 and 28. Overall, the platform supported long-term epithelial-endothelial culture and provided a stable, perfusable system for studying oBRB transport and cellular interactions.
Decellularized extracellular matrix (dECM) scaffolds are critical for tissue engineering and regenerative medicine, yet standardized methods for real-time monitoring of decellularization remain lacking. Current protocols typically use fixed treatment durations to match endpoint control quality attributes (CQAs), such as final dsDNA content in the scaffold, without a mechanistic understanding of DNA removal kinetics. This knowledge gap leads to either incomplete decellularization (CQA rejections) or unnecessary processing time, compromising dECM scaffold quality and process efficiency. In this paper, we develop a model-based mathematical monitoring framework for rapid assessment of DNase-treated porcine lung tissue that integrates dual-optical sensing of supernatant DNA release via ultraviolet-visible (UV-vis) absorbance and fluorescence. Decellularization supernatant was collected every 10 min over a 100-min treatment window in each sample group. Signals were well described by a first-order accumulation model C(t) = C0 + (Cmax - C0) (1 - e-kt), yielding an interpretable kinetic descriptor k and a model-based progress metric. A linear relationship was observed between the initial tissue mass and rate constant (R2 = 0.9998), enabling mass-aware prediction of release kinetics. When explored in dimensionless coordinates, normalized trajectories collapsed onto the universal curve f(τ) = 1 - e-τ that supports shared kinetics across sensing modalities. Model-derived in-process metrics were associated with endpoint residual tissue dsDNA quantified by QuantiFluor tissue digests and revealed an accessibility-limited gap between supernatant signal completion and tissue-level DNA removal within the treatment window. Together, these results provide the foundation of a practical process analytical technology style framework for quantitative decellularization monitoring and quality control, supporting mass-aware forecasting of process progress and adaptive protocol development.
Light-responsive hydrogel-based cell scaffolds enable noninvasive, high-precision microenvironmental editing through light stimulation. Two-photon excitation using near-infrared lasers has recently gained attention as a less cytotoxic light irradiation method for cells. Two-photon excitation is an optical phenomenon that generates a localized high-energy state through the simultaneous absorption of two long-wavelength photons, enabling precise manipulation at the single-cell level, even within thick gels. In this study, photodegradable gelatin acrylate (Gelatin-PDA) hydrogels incorporating o-nitrobenzylacrylate (PDA) photodegradation units into a gelatin scaffold were degraded via two-photon excitation. Upon light irradiation, the Gelatin-PDA hydrogel was degraded, loosening its network. We demonstrated that it can be precisely decomposed into both two-dimensional and three-dimensional patterns. By light-irradiating the surface and interior of the Gelatin-PDA hydrogel, we controlled the human bone marrow-derived mesenchymal stem cell (hBM-MSC) orientation along the pattern and mouse embryonic fibroblast (NIH3T3) spheroid elongation. In this study, we achieved the dynamic and precise control of the cell elongation direction within a three-dimensional cell scaffold by combining a Gelatin-PDA hydrogel with advanced two-photon excitation technology. This contributes significantly to complex and dynamic biological tissue mimicry and paves the way for advances in regenerative medicine.
Nerve guidance conduits (NGCs) represent a promising alternative to autologous nerve transplantation; however, their clinical efficacy remains limited by insufficient structural integrity and suboptimal fascicular guidance. Here, we report a novel extrusion-stretched strategy for fabricating multigrooved NGCs (MNGCs) reinforced with oriented multiwalled carbon nanotubes (MWCNTs). This scalable and controllable method effectively prevents conduit collapse during fabrication and enables precise regulation of conduit geometry, overcoming key limitations of conventional forming approaches. Incorporation of MWCNTs significantly enhanced the mechanical strength and biocompatibility of the conduits, as evidenced by improved Schwann cell (RSC96) viability, density, and pronounced aligned elongation compared with pure polycaprolactone (PCL) conduits. In a rat sciatic nerve defect model, the MWCNT-reinforced multigrooved NGCs (MMNGCs) achieved functional recovery, gastrocnemius muscle regeneration, and axonal myelination comparable to autografts while markedly outperforming single-lumen and groove-only PCL conduits. These results demonstrate that MMNGCs fabricated via the proposed extrusion-stretched strategy constitute a highly effective and clinically competitive platform for peripheral nerve repair.
Intervertebral disc (IVD) degeneration is a leading cause of low back pain (LBP), primarily originating in the nucleus pulposus (NP). Regenerative strategies combining mesenchymal stem cells (MSCs) with biomaterials offer great potential for NP repair by replenishing cells and restoring extracellular matrix (ECM). However, key translational challenges remain, including limited stem cell differentiation, poor cell survival in the harsh degenerative niche, and insufficient biomaterial support. While matrix viscoelasticity has been shown to influence adipose-derived stem cell (ASC) discogenic differentiation, its interplay with cell-adhesive ligands for IVD regeneration remains unclear. Moreover, most current hydrogels fail to replicate the ultrafast stress relaxation properties of native non-degenerative human NP tissue. Here, we developed viscoelastic ECM peptide-functionalized hydrogels (VEPH), specifically designed to mimic healthy human NP biomechanics and promote ASC differentiation for NP regeneration. We biochemically conjugated NP ECM-derived adhesive peptides (IKVAV, hA5G26, CHAD) through maleimide-thiol click chemistry, achieving hydrogels with significantly faster stress relaxation (∼25 s) compared to conventional viscoelastic alginate hydrogels (>100 s). Our results demonstrated that VEPH supported >95% ASC viability and robust metabolic activity over 21 days in 3D culture. Notably, the IKVAV-functionalized hydrogel significantly enhanced ASC cell-matrix interactions, upregulated NP marker expression (KRT18, HIF-1α, ITGA3, and CD24), and promoted type-II collagen secretion, indicating an NP-committed cell fate. Our findings highlight the synergistic roles of matrix viscoelasticity and NP-specific biochemical cues in directing ASC discogenic differentiation and advancing novel biomaterial design for IVD regeneration.
In this study, multifunctional composite coatings based on chitosan (CS), mesoporous bioactive glass nanoparticles (MBGNPs), and silver nanoparticles (AgNPs) were successfully deposited on Ti-13Nb-13Zr alloy by electrophoretic deposition (EPD). Two coating systems containing Eudragit E100 (EE100) or poly(4-vinylpyridine) (P4VP) were developed to tailor physicochemical and biological properties. The synthesized MBGNPs exhibited a spherical morphology with an average particle size of approximately 80 nm, as observed by TEM, while XRD analysis confirmed their amorphous structure. Both coatings formed uniform porous layers (∼10 µm thick) with excellent adhesion to the substrate (class 1, EN ISO 2409). Surface characterization revealed significantly increased roughness and distinct wettability behavior depending on polymer composition. CS/EE100 coatings exhibited hydrophobic character and low surface free energy, whereas CS/P4VP coatings showed highly hydrophilic behavior with increased surface energy. Electrochemical studies demonstrated enhanced electrochemical activity of coated samples, particularly for the P4VP-based system, associated with its porous and hydrophilic structure. Ion release studies confirmed time-dependent calcium release from MBGNPs and significantly higher silver ion release from CS/P4VP coatings, especially under acidic conditions. Both coatings exhibited strong antibacterial activity against Escherichia coli and Staphylococcus aureus, achieving up to ∼2.4 log reduction. Cytocompatibility studies using hFOB 1.19 osteoblast-like cells demonstrated that the CS/P4VP/MBGNPs/AgNPs coating maintained high cell viability (>80%) despite increased Ag+ release, while both coatings maintained alkaline phosphatase activity. Overall, the P4VP-based coating demonstrated the most favorable balance between antibacterial activity, ion release, and cytocompatibility, highlighting its potential for advanced biomedical implant applications.
Conjunctival tissue loss resulting from trauma, inflammatory diseases, or surgical interventions remains a major clinical challenge and highlights the need for reliable tissue substitutes. Additionally, advanced three-dimensional in vitro systems are required for studying conjunctival biology, evaluating therapeutics, and supporting the principles of the 3Rs. This study aimed to develop a hierarchically structured melt-electro-written (MEW) poly(ε-caprolactone) (PCL) scaffold as a platform for generating bilayered conjunctival constructs. The scaffold comprised a dense apical network to support epithelial attachment and a porous basal region to facilitate fibroblast infiltration and extracellular matrix formation. To enhance cell-material interactions, scaffolds were functionalized with a polydopamine coating. Morphology, surface modification, and mechanical properties were characterized by scanning electron microscopy, Raman spectroscopy, and tensile testing. Human conjunctival fibroblasts and epithelial cells were sequentially seeded to establish a bilayered model, followed by immunocytochemical evaluation. MEW enabled reproducible fabrication of thin scaffolds with defined apical and basal pore architectures. Compared with a conventional nonhierarchical box-pattern scaffold, the hierarchical design increased ultimate tensile stress from 0.32 to 0.83 MPa, reaching the mean value measured for fresh porcine conjunctiva, while producing little change in Young's modulus. PDA functionalization enhanced cellular attachment, spreading, and scaffold colonization. Sequential seeding generated a bilayer-like construct within seven days, characterized by preferential fibroblast integration within the porous basal region and formation of a CK13-positive epithelial layer predominantly localized to the dense apical surface. In conclusion, the developed scaffold supports the generation of bi-layered conjunctival constructs and represents a promising platform for conjunctival tissue engineering and standardized ocular surface models for advanced in vitro research.
Triple-negative breast cancer (TNBC) represents the most aggressive form of breast cancer and is associated with the worst prognosis. Ferroptosis holds great promise as an emerging therapeutic strategy; however, TNBC cells demonstrate reduced sensitivity to ferroptosis as a result of elevated mitochondrial membrane potential (MMP), inadequate production of reactive oxygen species (ROS), and the presence of activated antioxidant defencses, making it difficult for lipid peroxidation to accumulate to a lethal threshold. As an emerging therapeutic strategy, sonodynamic therapy (SDT) is particularly suitable for deep-seated tumors due to the excellent tissue penetration capabilities of ultrasound (US). Nevertheless, current sonosensitizer typically experience limited sonodynamic efficacy and inadequate targeting of tumors, whereas small interfering RNA (siRNA) presents a highly promising option for gene therapy, its efficacy is heavily dependent on efficient and safe cellular delivery vectors. Therefore, we designed and synthesized a folate-modified Fe-TCPP metal-organic framework (FTFA) nanoplatform that serves both as a siATAD3A gene therapy carrier and as a sonosensitizer to generate ROS upon ultrasound (US) irradiation. ATAD3A displays high expression levels in TNBC and is linked to a negative prognosis; it's silencing reduces MMPs and increases ROS-induced apoptosis. siATAD3A was loaded onto FTFA to prepare FTFA@siATAD3A, which was delivered to TNBC cells via folate receptor-mediated targeting. Under US irradiation, the Fe3+ loaded within this platform synergistically triggers a ferroptosis cascade involving the Fenton reaction, lipid peroxidation, and GPX4 downregulation, effectively inducing ferroptosis. This method greatly reduces the proliferation of cells, as well as their migration and tumor growth when tested in living organisms, and it also shows excellent compatibility with biological tissues. In summary, FTFA@siATAD3A provides a novel strategy for the synergistic gene-ferroptosis therapy of TNBC using sonodynamic effects.
Osteoporosis, featured by imbalanced bone remodeling, faces clinical challenges including microenvironment dysregulation, insufficient mineralization, and poor material fixation. Inspired by natural bone regeneration-where ossification centers and surrounding soft tissues orchestrate mineralization and tissue integration-we herein develop a biomimetic adhesive in which strontium titanate (SrTiO3) serves as the mineralization core to mimic ossification centers, boosting biomineralization and osteoblast differentiation. Meanwhile, poly(lipoic acid) (PolyLA), synthesized via one-step polymerization of lipoic acid (LA), replicates the role of soft tissues for structural support and biological regulation. Multiple coordination interactions between carboxyls and strontium ions substantially reinforce this organic-inorganic composite, resulting in a compressive strength, toughness, and tear resistance 11.65-fold, 9.1-fold, and 2.76-fold higher than those of pure PolyLA, respectively, thereby resisting anisotropic mechanical stresses at osteoporotic sites under physiological locomotion. Additionally, its hot-melt injectability enables robust interfacial fixation to osteoporotic bone, achieving an adhesion strength of up to 1.3 MPa, and facilitates sustained co-release of Sr2+ and LA, conferring anti-inflammatory, antioxidant, and pro-angiogenic functions. In an osteoporotic rat femoral defect model, this adhesive outperforms commercial bone cement by accelerating bone regeneration, improving microarchitecture, and increasing bone density. Its biocompatibility, degradability, mineralization capacity, and stable fixation offer a biomimetic strategy for osteoporosis treatment.
Silk fibroin (SF) hydrogels have attracted widespread attention as promising wound dressings owing to their excellent biocompatibility and tunable structure. However, constructing SF hydrogels with easily adjustable mechanical properties and clarified structure-function relationships remains challenging. Herein, we fabricated a series of mechanically tunable SF hydrogels using ethylene glycol diglycidyl ether (EGDE) as a biocompatible crosslinker. The epoxy groups of EGDE readily react with the nucleophilic amino and hydroxyl groups on SF chains via ring-opening reactions, forming stable covalent crosslinks. By systematically optimizing the SF concentration, crosslinker molar ratio, and reaction temperature, hydrogels with well-defined porous architectures, stable crosslinked networks, and favorable biosafety were obtained. Among them, the 150-90-1 hydrogel exhibited optimal comprehensive performance, with a compressive strength of ∼250 kPa, a tensile strength of ∼280 kPa, and an adhesion strength of ∼4.5 kPa to porcine skin. In vitro results confirmed that the hydrogel had cell viability above 90% and supported cell survival and proliferation. In vivo experiments using a mouse full-thickness skin wound model demonstrated that the hydrogel significantly accelerated wound closure, attenuated inflammatory infiltration, promoted re-epithelialization and collagen deposition, and enhanced angiogenesis by upregulating VEGF (28% at day 3; 47.8% at day 12) and CD31 (14.5% at day 3; 24.5% at day 12) while downregulating IL-6. Mechanistically, the negatively charged SF backbone enriched the positively charged endogenous VEGF through electrostatic interactions, and the hydrogel acted as a protective physical barrier to maintain a stable wound microenvironment. This work provides a facile strategy for developing mechanically adjustable SF hydrogels and elucidates their regulatory mechanism in wound repair, highlighting their great potential as safe and effective wound dressings.
Polyhydroxyalkanoates (PHAs) are biopolyesters that accumulate as cytosolic cell inclusions in many bacteria, enhancing resistance to environmental stresses. However, the structure, spatial localization, plasticization effects, and mechanical properties of PHA granules in vivo remain underexplored. Here, Cupriavidus necator H16 grown under nutrient-rich and limited conditions was investigated across a 72 hour accumulation cycle using orthogonal techniques including atomic force microscopy infrared (AFM-IR) spectroscopy, contact resonance mechanical analysis, optical photothermal infrared spectroscopy, nano-thermal analysis, and proteomics to map polyhydroxybutyrate (PHB) granule evolution. Across the PHB production cycle, the PHB content increased from 34 to 69% after 72 hours in minimal media, while in vivo crystallinity reached a maximum of 20% compared to 42-63% when extracted. Ester carbonyl band shifts (1720-1740 cm-1) indicated mostly amorphous PHB in vivo, while contact resonance mapping showed that the granules were mechanically softer than the surrounding cellular matrix. Notably, AFM-IR revealed membrane patterning consistent with spinodal decomposition, representing the first reported observation of spinodal-like membrane organization in C. necator. Proteomics identified increased production of PHB biosynthesis, regulation, and phasin proteins during the stationary phase, supporting phasin-assisted suppression of crystallization. Whole-pathway analysis further revealed stronger perturbations in formate oxidation and polyphosphate metabolism than in PHB biosynthesis alone, highlighting broader metabolic shifts. This study establishes a link between PHB accumulation, crystallinity, mechanical softness, and granule-associated protein production in C. necator, yielding a plasticized intracellular polymer state relevant to flexible bioplastic and biomedical material design.
New Ru(II) arene complexes, namely, Bis(η6-p-cymene)-3,3'-((2,4,6-trimethyl-1,3-phenylene)bis(methylene))bis(1-(pyridin-2-ylmethyl)-1,3-dihydro-2H-benzo[d]imidazol-2-thione)(dichloro)ruthenium(II) dichloride (Ru-BIS) and 1-isopropyl-3-(pyridin-2-yl)-1,3-dihydro-2H-naphtho[2,3-d]imidazol-2-thione(chloro)ruthenium(II) chloride (Ru-NIS), were synthesized and characterized by various spectral techniques. The single-crystal X-ray diffraction structures substantiate a piano-stool octahedral geometry around the Ru(II) center of the complexes. The electronic spectra of Ru-BIS and Ru-NIS showed characteristic metal-to-ligand charge-transfer (MLCT) bands at 436 and 453 nm, respectively. The measured octanol/water distribution coefficient (log D) values for Ru-BIS and Ru-NIS demonstrated a marked enhancement of their aqueous solubility compared to their respective ligands (BIS and NIS). The stability studies of the complexes in D2O/DMSO-d6 (9:1) indicated a rapid aquation followed by the formation of a stable hydrolyzed species under physiological conditions. Ru-BIS and Ru-NIS bind strongly and statically to the bovine serum albumin (BSA) protein (Kb ∼ 105 M-1) with one ligand per binding site. Cell viability studies revealed that both Ru-BIS and Ru-NIS are biocompatible with non-malignant cells (C2C12 and L929), in defined concentration ranges. Furthermore, Ru-BIS (IC50 = 0.05 mg/mL, 40.31 μM) exhibited greater cytotoxicity against B16 melanoma cells compared to Ru-NIS (IC50 = 0.135 mg/mL, 215.78 μM). Microscopic evaluations of melanoma cells treated with Ru-BIS and Ru-NIS revealed that the former exhibited more mitochondrial dysfunction, apoptotic induction, and DNA double-strand breaks.
Conventional wound dressings often fail to integrate rapid hemostasis, antibacterial protection, and a pro-regenerative microenvironment, leading to persistent infection and delayed healing in complex wounds. Herein, we report a multifunctional self-adhesive hydrogel for integrated hemostatic, antibacterial, and regenerative wound management with a synergistic dual-crosslinked network. The hydrogel is composed of methylacrylamide-modified type I collagen (ColMA), o-nitrobenzene-modified hyaluronic acid (HANB), and methylacrylamide-modified chitosan (CSMA), and can rapidly form in situ under UV irradiation through free-radical polymerization of methacrylamide groups and Schiff base reactions between HANB and amino groups on ColMA/CSMA. Once applied to infected wounds, the hydrogel rapidly seals the wound bed and adheres tightly to the tissue, where HANB contributes hemostatic and adhesive properties, CSMA provides intrinsic antibacterial activity to inhibit bacterial colonization, and ColMA offers extracellular matrix-mimicking cues to support cell adhesion and tissue regeneration. Through this coordinated mechanism, the hydrogel not only controls bleeding and reduces infection risk at the early stage but also promotes the growth of granulation tissue, re-epithelialization, and matrix reconstruction during the subsequent repair phase. This platform integrates wound closure, antibacterial defense, and tissue regeneration into a single dressing system, acting as a promising strategy for the treatment of infected wounds.
Diabetic chronic wounds have become a major challenge for clinical treatment due to their complex pathological microenvironment, including persistent inflammatory response, angiogenesis disorder, excessive oxidative stress, and susceptible infection. Traditional dressings as a passive barrier have difficulty meeting the above multiple treatment needs. Electrospinning technology, with its ability to mimic the fibrous network structure of the natural extracellular matrix (ECM), offers a high specific surface area, controllable porosity, and excellent drug-loading capacity, making it an ideal platform for developing a new generation of multifunctional wound dressings. This article provides a systematic review of the research progress on electrospun nanofiber dressings in the treatment of diabetic wounds, focusing on the design evolution from basic single-layer structures to advanced complex structures and elucidating the mechanisms of action and quantifiable effects of each structural type in addressing specific pathological challenges. We also compared the current status of clinical translation for electrospun dressings with that of other advanced wound care platforms and proposed a standardized preclinical evaluation framework. A large number of research data show that these advanced designs can effectively improve the quality of healing. Finally, this paper points out the challenges faced by this field, such as scalable fabrication, in vivo reliability of smart systems, and long-term biosafety, and provides theoretical basis and technical reference for the design of efficient and intelligent electrostatic spinning diabetic wound dressings.
Single-domain antibodies (sdAbs) derived from naive phage display libraries offer a time-efficient alternative to animal immunization but often exhibit suboptimal affinity, particularly for small-molecule haptens, where restricted binding interfaces limit the efficacy of traditional saturation mutagenesis. For instance, the wild-type sdAb (B1)-targeting ethoxyquin (EQ) exhibits a moderate equilibrium dissociation constant (KD) at the submicromolar level (within the 10-7 M range), restricting its practical sensitivity. To overcome the structural and energetic barriers inherent in hapten recognition, a "structure-guided directed modification" strategy was developed that focuses on conformational tuning rather than simple side-chain replacement. Integrating AlphaFold2 modeling and AutoDock mechanistic analysis identified key interactions (e.g., the ASP19-EQ-N8 hydrogen bond). Subsequently, a random single-amino acid insertion strategy was implemented within the CDR3 loop (residues 77-90) to fine-tune local loop geometry. Top candidates were screened via MM/GBSA binding free energy calculations and experimentally validated using biolayer interferometry. This approach yielded three high-affinity mutants-77A, 79C, and 85H-with calculated ΔΔG values of -10.56, -4.35, and -6.69 kcal/mol, respectively. The mutants achieved enhanced affinities in the tens-of-nanomolar range (down to 35.1 nM), representing up to approximately 3 times overall improvement. Importantly, orthogonal surface plasmon resonance analysis using nonconjugated, free EQ successfully verified this affinity maturation trend, showing that mutant 79C bound free EQ with a KD of 1.30 × 10-5 M (a 2.3 times improvement over wild-type) through simultaneously accelerated association and slowed dissociation. Mechanistically, this substantial increase in affinity is attributed not only to reinforced noncovalent networks that significantly stabilize the complex but also to favorable CDR3 geometric outward flips that alleviate steric hindrance, leading to an approximate 3.8 times acceleration in the kon. Crucially, these mutants demonstrated notable anti-interference tolerance in complex aquatic food matrices (e.g., sea bass extracts). Ultimately, this work provides a practical and efficient computational framework for assisting the rapid evolution of low-affinity hapten sdAbs into high-performing biorecognition elements with potential for next-generation biosensing architectures.
In this study, a three-dimensional viscoelastic lattice spring model (VLSM) is employed to evaluate the transferability of compression-calibrated material parameters to shear loading for poly(methyl methacrylate) (PMMA)-based bone cement (BC). The model is first calibrated using compressive stress-strain data and then applied to shear loading without further parameter re-identification. The model reproduces the main features of the compressive response, predicts the shear stress-strain response, and resolves the associated progression from homogeneous elastic deformation to diffuse microdamage and ultimately to localized failure. Moreover, analyses considering variations in shear location and shear-plane size further clarify the relationship between shear stress-strain response and damage patterns, revealing that more peripheral loading and smaller shear planes sustain higher load-carrying capacity due to differences in crack propagation pathways. Finally, parametric investigations demonstrate that loading rate, porosity, and BaSO4 content exert systematic influences on the macroscopic stress-strain response and damage development. These findings suggest that the VLSM can transfer a compression-calibrated parameter set to shear loading, enabling analysis of the shear mechanical response and damage evolution of PMMA-based BC.
Osteoarthritis (OA) is characterized by a chronic inflammatory microenvironment with excessive reactive oxygen species (ROS) and progressive cartilage degeneration. To address these challenges, we developed a ROS-responsive, water-oil biphasic separable microneedle patch (CKCA MN) for transdermal therapy. This microneedle utilizes hyaluronic acid (HA) as a rapidly dissolving substrate, and its needle tip comprises a coordination-crosslinked hydrogel formed by Ce3+ and alendronate (Aln), loaded with cinnamaldehyde (CM) as the oil-phase carrier encapsulating kartogenin (KGN). The needle tip can rapidly dissociate from the base and selectively remain in the dermis, enabling localized therapeutic delivery for OA. Within the needle tip, the aqueous phase degrades under the trigger of ROS. Ce3+ efficiently scavenges ROS via the Ce3+/Ce4+ redox cycle, while Aln binds to the bone surface and suppresses osteoclast activity. Concurrently, the oil phase can directly neutralize ROS and facilitate sustained release of KGN, which drives chondrogenic differentiation of endogenous progenitor cells. Critically, the oil phase can precisely regulate the degradation kinetics of the Ce-Aln hydrogel, thereby establishing a dual-phase release curve: Ce3+-driven anti-inflammatory effects followed by KGN-mediated cartilage matrix synthesis and structural restoration. The presence of the oil phase can reduce the degradation rate of the needle tip, from 24 to 120 h of degradation release. The treatment with the CKCA MN resulted in a 3-4-fold decrease in inflammatory factors and cartilage remodeling. Collectively, the CKCA MN leverages ROS-responsive degradation to spatiotemporally regulate drug release, thereby achieving a synergistic therapeutic cascade of "anti-inflammation, subchondral bone protection, and cartilage regeneration," which addresses the interconnected pathological mechanisms underlying OA progression.
